Tree cross-cutting blade assembly

ABSTRACT

Tree cross-cutting blade assembly are each trough-shaped with outwardly inclining sides leading from a bottom of the trough which slopes downward and terminates as the blade cutting edges. The blades are mounted for movement towards one another along paths which are substantially straight when viewed in a horizontal direction so that a portion of the tree between the troughs is compressed to alleviate splitting while it is being cut.

[ 1 Sept. 12, 1972 54] TREE CROSS-CUTTING BLADE 3,590,894 7/1971Boyd........................144/3963 ASSEMBLY [7 2] Inventors: John S.Johnston; Andre St-Laurent,

w D Ma flh an GH HR mm m J 3 3 MW 0mm both of Ottawa, Ontario, Canada[73] I Assignee: Canadian Patents and Development Ottawa, Ontario, [57]ABS CT Tree cross-cutting blade assembly are each trough- Limited,Canada shaped with outwardly inclining sides leading from a 22 Filed:Oct. 19,1970 21 Appl.No.: 81,774

bottom of the trough which slopes downward and terminates as the bladecutting edges. The blades are mounted for movement towards one anotheralong 52 US. Cl. Paths which are substantially Straight when viewed in a144/34R [51] Int. 23/02 ntal d re ti n so that a portion of the tree[58] FieldofSearch...........................144/34R, 34E between thetroughs is compressed to alleviate splitting while it is being cut.

5 Claims, 2 Drawing Figures References Cited UNITED STATES PATENTS3,540,501 11/1970 Jonsson....................144/34E TREECROSS-CUTTINGBLADE ASSEMBLY This invention relates to a tree cross-cutting bladeassembly.

In tree harvesting, rising labor costs have spurred the industry toinvest heavily in mechanization. In the felling of trees, for example,tractor mounted tree cross-cutting blades have begun to replace thechain saw because they are faster and lend themselves better toautomation.

A major disadvantage with tree cross-cutting blades has been the highdegree of splitting damage that has been encountered, particularly whentrees are felled by such blades during very cold weather.

It is an object of the invention to provide tree crosscutting bladeswherein damage due to splitting is alleviated.

It will be appreciated that damage due to splitting is only undesirableon the portion of the tree being harvested, that is on the portion ofthe tree that is severed from the stump. Thus it is sufficient forsplitting damage to be alleviated from the portion of the tree beingharvested even if this is accomplished at the expense of furthersplitting being incurred in the stump.

The invention provides a tree cross-cutting blade assembly, wherein atleast a portion of each blade is trough-shaped with each trough havingoutwardly inclining sides leading from a trough bottom incliningdownwardly towards and terminating at a tree cutting edge of that blade,and the tree cutting edge forming an open end of that trough forcompressing the portion of a tree being cut between the cutting edges,whereby splitting is alleviated in the portion of the tree beingcompressed.

In the accompanying drawings which illustrate, by way of example,embodiments of the invention,

FIG. 1 is a perspective view of a tree cross-cutting blade assembly, and

F IG. 2 is a perspective view of a different tree crosscutting blade.

In FIG. ltwo tree cross-cutting blades 1 and 2 are trough-shaped at 4and 6 respectively with dependent lower sides. Each trough 4 and 6 hasoutwardly inclining sides 8, 9 and 10, 11 leading from trough bottoms l3and 14 respectively which incline downwardly towards and terminating astree cutting edges 16 and 17. The tree cutting edges 16 and 17 form openends of the troughs 4 and 6 for compressing the portion of the treebeing cut between the cutting edges 16 and 17 the blades 1 and 2 are ofuniform thickness and are preferably pressed from flat plate. As will bedescribed later, splitting is alleviated in the portion of the treebeing compressed.

The blades 1 and 2 are secured by flat portions and 18 in holders 19 and20 respectively by clamping plates 22 and 23 and bolts 25 and 26. Thetroughs 4 and 6 terminate at the flat portions 15 and 18. The bolts 25and 26 extend through clearanceholes (not shown) in the clamping plates22 and 23 and blades 1 and 2, and are screwed into threaded holes (notshown) in the holders l9 and 20. The holders 19 and 20 are each slidablymounted by T-flanges, one of which is shown and designated 28, in aT-slot 29 in a mounting bar 30. It will be appreciated that, althoughnot shown, the end stops are provided at each end of the T-slot 29 toprevent the T-flange 28 from sliding out of the ends of the T-slot 29.

The holders l9 and 20 are pivotally attached to an oil operated, doubleacting piston 32 and cylinder 33 by pivots 35 and 36 respectively. Thecylinder 33 is connected by means not shown to the conventionalpressurized oil feed of a tractor.

In operation the blades 1 and 2 are mounted as shown in FIG. 1 and thenmoved to position a tree (not shown) to be felled between them, thepiston 32 and cylinder 33 are then activated to move the blades 1 and 2together along paths which are substantially straight when viewed in ahorizontal direction. As the blades 1 and 2 move together the portion ofthe tree between the tree cutting edges 16 and 17 is compressed betweentroughs 4 and 6 to alleviate splitting. It will be ap-,

preciated that the splitting is alleviated in this manner at the expenseof further splitting being incurred in the stump dependent undersides ofthe blades 1 and 2, but this is not objectionable because the stump isnot utilized.

The blades 1 and 2 may be activated by a different mechanism, forexample, the blades 1 and 2 may be pivotally mounted on a scissor-typemechanism to move along horizontal paths. The tree cutting edges 16 and17 are shown shaped by chamfering both side faces of each blades 1 and2, however, other shapes of cutting edges may be used such as, forexample, cutting edges formed by chamfering the blades on one side only.

In FIG. 2 similar parts to those shown in FIG. 1 are designated by thesame reference numerals, and the previous description is relied upon todescribe them.

A blade 38 has a trough 40 with outwardly inclined sides 42 and 44leadingfrom a trough bottom 46. The trough bottom 46 is V-shapedincross-section in this embodiment, insteadof being U-shaped incross-section as in the previous embodiment. As in the previousembodiment the trough bottom 46 inclines downwardly towards a treecutting edge 48 forming an open end of the trough 40, for compressing aportion of a tree between them during cutting.

Two blades similar to blade 38 are mounted in the same manner as theblades 1 and 2 are shown mounted in FIG. 1 in holders l9 and 20, and areused in the manner previously described with reference to FIG. 1. Theblade 38 tends to compress the portion of a tree to a greater extentthan the blades 1 and 2 (FIG. 1) because of the V-shaped trough bottom46.

Whilst the troughs shown in FIGS. 1 and 2 are tapered to increase incross-section towards the cutting edges, it is within the scope of theinvention to use blades having troughs of uniform cross-section.

, A possible explanation why the tree does not tend to split when it iscompressed between the troughs is that the wood is compressed more orless radially inwardly.

Using trough-shaped blades according to the invention has the advantagethat more wood can be included in the stem because of the convex shapedend of the harvested wood, than is harvested by conventional flatblades.

What is claimed is:

1. Tree cross-cutting blade assembly, wherein at least a portion of eachblade is of uniform thickness and is trough-shaped with dependent lowersides, each trough having outwardly inclining sides leading upwardlyfrom a trough bottom, with the trough bottom extending downwardly alongan incline towards and terminating at a tree cutting edge of that blade,and the tree cutting edge forming an open end of that trough, andmounting means mounting the blades for movement towards one anotheralong paths, which are substantially straight when viewed in anhorizontal direction, for compressing a tree being cut by the cuttingedges, in the troughs, by the top surface which is inclined with respectto the direction of motion, thereby causing more splitting of theportion of the tree adjacent the claim 1, wherein each trough isU-shaped in cross-section.

3. Tree cross-cutting blade assembly according to claim 1, wherein eachtrough is V-shaped in cross-section.

4. Tree cross-cutting blade assembly, according to claim 1, wherein eachtrough is tapered to increase in cross-section towards the cutting edge.

5. Tree cross-cutting blade assembly according to lower dependent Sidesthan that adjacent the upper claim 1, wherein each trough terminates ata flat inclined sides of the blades.

2. Tree cross-cutting blade assembly according to clamping portion ofthat blade for the mounting means.

1. Tree cross-cutting blade assembly, wherein at least a portion of eachblade is of uniform thickness and is trough-shaped with dependent lowersides, each trough having outwardly inclining sides leading upwardlyfrom a trough bottom, with the trough bottom extending downwardly alongan incline towards and terminating at a tree cutting edge of that blade,and the tree cutting edge forming an open end of that trough, andmounting means mounting the blades for movement towards one anotheralong paths, which are substantially straight when viewed in anhorizontal direction, for compressing a tree being cut by the cuttingedges, in the troughs, by the top surface which is inclined with respectto the direction of motion, thereby causing more splitting of theportion of the tree adjacent the lower dependent sides than thatadjacent the upper inclined sides of the blades.
 2. Tree cross-cuttingblade assembly according to claim 1, wherein each trough is U-shaped incross-section.
 3. Tree cross-cutting blade assembly according to claim1, wherein each trough is V-shaped in cross-section.
 4. Treecross-cutting blade assembly, according to claim 1, wherein each troughis tapered to increase in cross-section towards the cutting edge. 5.Tree cross-cutting blade assembly according to claim 1, wherein eachtrough terminates at a flat clamping portion of that blade for themounting means.